Contact device for electric traction systems.



H. S. FARQUHAR.

CONTACT DEVICE FOR ELECTRIC TRACTION SYSTEMS. APPLICATION FTLED 1111.2. 1915.

1,176,440. Patented` Mar. 21, 1916.

IHNEN i HENRY s. rana-Unna, or WAYNE, rnNNsvLvnNra.

CONTACT DEVICE FOR ELECTRC TEACTION SYSTEMS.

Application filed January 2, 1815.

residing at Wayne, in the county of Dela- `ware andv State of Pennsylvania, have invented certain new and useful improvements in Contact Devicestory Electric Traction Systems, whereof the following is a specification, reference being had to the accompanying drawings.

My invention is intended for use in connection with so-called `third rail systems, wherein a traveling collector shoe is ernployed to malte electrical contactvvith the surface of an iron conductor.

The object oi' the inventionis to insure efficiency ofcontact under the conditions experienced in these systems, When sleet, ice, snovv or other foreign substances accumulate Vupon the contacting surfaces, the effect thereof sometimes being such as to greatly impair if not Wholly destroy the e'liiciency of the electrical contact.

Various adjunctive devices have been de- I signed to overcome the diiliculty referred to,

as for instance, auxiliary springs, orrair cylinders with pistons; such devices being -in-V tendedto supply additional mechanical pressure to the amount normally required. The organization essential to the embodiment of these devices adds to the complication of the structure, and also to the Weight of the apparatus as a, whole. Furthermore if a high degree of mechanical pressure be employed, such devices cannot practically be used on light conductors, or Where the supports of the conductors are far enough apart to permit bending of the latter.

My present invention attains the desired end and avoids these diiiiculties by providing means, whereby, Without substantially increasing the Weight or complication of the mechanical devices, normally employed to insure proper contact, and Without augmenting the normal mechanical strain transverse to the conductor, the contact pressure between the conductor and the traveling element may be intensified Whenever desired, and to the extent desired, by magnetic attraction.

ln the accompanying drawings, I have illustrated an embodiment of the invention in its preferred form.

ln said drawings, 1Figure I, represents a vertical sectional View through the mounting and retaining: devices of a preferred form of shoe, the third rail being also partly specification of Letters raient.

Patented Mar. 2i, 1916.

serial No. es.

indicated in section. F ig. Il, is a horizontal section on the line Il, il, oi' F ig. l, showing dlagrammatically an electric circuit adapted Ior use 1n such an embodiment of the inventiont `The third rail is indicated at l, and is assumed to be oi iron, or a compound possessing magnetic properties similar to those of iron. The slice or traveling collector, in this embodiment is a double one, comprising the tivo elongated contact pieces 2, and 3, of iron or low carbon steehwhich are respectively provided with rearwardly projecting bolts 4l, and 5, of iron, or similar magnetizable material. Said bolts are adapted to be secured by means of nuts 6, and 7, in down- Wardly depending lugs 8, and 9, cast integral With, or attached to, the horizontal tubular rock-shaft 10. The tubular rock-shaft 10, is supported upon an axial spindle 11, whose ends are mounted in depending brackets, one of which, 12, is shoivn in Fig. l, said brackets being hung frcmthe under side of a portion 13,701l the vehicle.

el roclr-arm 15, is made integral With or secured to the tubular rock-shaft l0. the outer end of said arm being pivotally attached at 17, to a plunger 1S, adapted to slide axially in a hollow cylindrical supporting piece 19, having a lug 20, pivoted at 421, to a portion of the bracket 12. A coiled spring 22,v seated Within the cavity of the supporting piece 19, tends normally to thrust the plunger 18, outward or toward the point of attachment to the rock-arm 15. Hence When the parts are in the position shown in Fig. I, the pressure-oi:l the spring 2Q, tends to maintain the shoe members 2, and 3, in Contact With the upper surface of the third rail 1. lNhen, however, the shoe is raised from the rail by turning the tubular rockshaiit 10, upon its axis 11, the motion transmitted through the rock-arm 15, compresses the spring 22, untilthe dead point at the pivot 17, is passed, and thereupon the normal pressure of the spring protruding the plunger 18, tends to retain the shoe in retracted or non-contacting position. While this particular method of maintaining the shoes in either the contacting or retracted position has no direct bearing upon the subject matter of the present invention, it serves both to illustrate a preferred form of embodiment and to point out the reasons which render the present invention desirable.

T he shoe members 2, and 3, and their rearwardly projecting bolts 4, and 5, are conshoe member, I surround its bolt with a coil ioI of insulated wire as shown at 25, and 26, the two coils being connected in series. as indicated at 27. A lead 2S', forms an electrical connection betweenthe shoe member 3, and the coil 26. K

From the remote terminal 29, ofthe other lcoil 25, a circuit is arranged, shown in this instance, as leading through a switch 31, varying resistance 32, and switch arm 33, to ground at 34. Said circuit is thus in shunt relation to the motor circuit supplied from the third rail.

'llie shunt circuit thus derived and controlled by means of the variable resistance 32, energizes the two electromagnetic coils 25, and 26, and magnetizes their cores which, -in this instance, comprise the shoe members 2, and 3, and their rearwardly projecting bolts 4, and 5. The local magnetic attrae* tion between the shoe members and the third rail tends to hold the former in close contact with the surface of the rail, thus supplementing the action due to the weight of the shoe and to the pressure of the spring 22. {Asthe switch 3l, and resistance 32, are so located as to be under the control of theV inotorman upon the vehicle, he can apply, vary, and throw olip the extra contacting pressure in accordance with the conditions presented. The additional pressure thus developed 'holds the slices in forcible contact with the rail so that the foreign substances areV disposedV and the electrical Vefficiency of the contact enhanced.V i l i In the embodiment just described, the shoe is a doubleone, comprising two similar contacting 'members This form is one which I have found in practice to be desirable.V It is obvious however, that this duplication of the contacting element is not essenti'alv and that the invention lends itselfV to use in connection with a shoe consisting of a single such element.

In either case if it be assumed that the weight of the shoe and character of the mechanical-.device for obtaining contact under normal circumstances, is the proper one for the conditions of la given system, in that nthe actual weight ofthe parts is at the `miniv mum, and the mechanical structure of the simplest permissible form, and that the organization is adapted to produce efficient contact under normal circumstances, the employmentofmy invention insures efficient Contact under abnormal conditions, without substantially adding to the weight of the parts, and with butV trifling modifications of the structure itself. l.

I am aware that it is not broadlyV speaking new to utilize magnetic attraction as'the means for obtaining normal contact between a traveling` collector and a conductor, and

Iftlie-refo-re do not broadly claim the same.

In order to conveniently indicate the es-V sential'properties of the material of which the fixed 'and traveling elementsrare coinprised, I shall employ the term `magnetizable, meaning therebythait one of such elements is capable of becoming in whole or in part, an electro-magnet, ,and the other of acting in whole or in part as an armature of saidmagnet.

Having thus described my invention, I

claim:

comprising inagnetizable material arranged in magnetically operative relation to said fixed conductor; mechanical means for causing said collector to vbear against said conductor with normally suilicient pressure,

independently of magneticV attraction; an electi-o-n'iagnet coil upon said travelingrcollector; a soureeof yelectricity in circuit with said coil; and means for controlling said circuit.

2. In an electric traction system, tlie combination of a fixed conductor comprising magnetizable material; a ,travelingv collector comprising magnetizable material Varranged Vin magnetically operative relation toV said fixed conductor mechanical means for causing said collector to bear against said conductor with normally suilicient pressure,'in

depeiidently of magnetic attraction; an

faces in contact,independently of magneticV attraction; an electro-magnetic coil for said traveling element; an electric circuit for Asaid coil; and means for controlling said circuit. Y.

In testimony whereof, I have hereunto signed my name, at Philadelphia, Pennsylvania, this thirtieth day of December,1914.v

HENRY S. FARQUHAR. Witnesses: Y. .Y Y l JAMES H. BELL, Y i L.,FULLERT0N.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner Vof Patents, i i 'i Washingtonfl). C. i I l vllO iis

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